Mammoth Lake
Key Takeaway
Mammoth Lake is classified as high hazard in Pennsylvania. It was completed in 1969 and is 57 years old. Its primary use is recreation. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.
Physical Details
| Dam Height | 15 ft (taller than 27.6% in PA) |
| Dam Length | 1,100 ft |
| Dam Type | Earth |
| Max Storage | 342 acre-ft |
| Normal Storage | 182 acre-ft |
| Surface Area | 27 acres |
| Drainage Area | 9 sq mi |
| Year Completed | 1969 (57 years old) |
| NID ID | PA00466 |
Safety Information
Loss of human life is likely if the dam fails.
Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?
Ownership
WESTMORELAND COUNTY COMMISSIONERS
Local Government
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High Hazard 32 ftFrequently Asked Questions
What is the hazard classification of Mammoth Lake?
Mammoth Lake is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.
Who owns and operates Mammoth Lake?
Mammoth Lake is owned by WESTMORELAND COUNTY COMMISSIONERS (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Mammoth Lake built?
Mammoth Lake was completed in 1969, making it 57 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.
What is the primary purpose of Mammoth Lake?
Mammoth Lake serves the following purposes: Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Mammoth Lake?
Mammoth Lake has a dam height of 15 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.
When was Mammoth Lake last inspected?
Mammoth Lake was last inspected on August 12, 2019. Inspection dates indicate when a formal review occurred, not the results of that inspection.